The aerospace industry in the United States is rapidly being confronted with obsolete fabrication technology and equipment that cannot keep pace with the technological requirements of today's and tomorrow's aircraft requirements. Each year the machine tool industry encounters new demands of engineers who specify increasingly complex machining processes for the manufacture of metal parts. One of greatest challenges confronting designers in the precision metal working industry is finding more precise and dependable techniques to cut or to bore metal or plastic parts that may have exceedingly small dimensional tolerances or that may be fabricated from exotic alloys, such as titanium, Inconel.TM. or hybrid stainless steels. The aircraft and aerospace industries are constantly confronted by difficulties that arise when hollow cylindrical metal conduits need to be severed or when a precise recess must be formed in a plastic or metal part.
Titanium and its alloys have material properties that make it especially desirable for special applications, particularly within the aerospace industry. First, titanium has a high strength-to-weight ratio, which makes it comparable to many steels and stainless steels, while being only about 56 percent as heavy. While titanium alloys are about 40 percent heavier than aluminum, their greater strength allows much less material to be used for many applications. Titanium alloys also possess good corrosion resistance, and high heat performance which makes them even more desirable for aerospace applications.
Despite the desirable properties that titanium alloys possess, the high cost of the material and difficulties with production and fabrication with titanium alloys have limited their widespread use. Titanium alloys tend to be very unforgiving when standard fabrication methods are employed. They are at least as difficult to work with as hybrid stainless steel alloys.
Several previous attempts to solve the problem of providing effective, high-precision cutting and boring tools have met with mixed results.
In U.S. Pat. No. 5,209,617, Heule describes a deburring tool that includes a knife housing that extends downward. Heule states that his invention is designed to debur bores of a "significantly reduced diameter".
In U.S. Pat. No. 4,162,867, Calcaterra et al. disclose a dual cutter boring head which comprises a cylindrical body having side-by-side, tool-holding slides mounted diametrically on the boring head.
In U.S. Pat. No. 4,375,773, Liemann describes an oscillating cutting toolhead having an oscillating cutter which includes two blades which are prestressed radially inwardly.
In U.S. Pat. No. 4,741,231, Patterson et al. disclose a tool force sensor assembly that generates an electrical signal which is related to the change in force applied by a tool to a workpiece. The signal indicates the wear condition or failure of the tool.
In U.S. Pat. No. 4,637,285, Mizoguchi describes an automatic feed device for a facing head comprising a shank mounted to the main shaft of a machine tool.
In U.S. Pat. No. 4,612,831, Lehmkuhl discloses a boring machine having a tapered shank that is received in a spindle with a pre-loaded adjustable boring bar.
In U.S. Pat. No. 3,710,659, Pagella et al. describe a tool holding device in which the tool slides in the holder to enable a radial motion with respect to the axis of rotation of a holding device.
A Patent issued by the Soviet Union in 1979 entitled "Diamond-Reaming" (No. 0880636) depicts a head comprising a boring cutter which is mounted in a cover.
The problem of providing a high-precision tool that can be used to cut and bore metals, plastics, composites and other materials has presented a major challenge to engineers and technicians in the materials industry. The development of an accurate and versatile system that overcomes the difficulties encountered when conventional cutters or boring machines are utilized would constitute a major technological advance in the metal fabrication business. The enhanced performance that could be achieved using such an innovative device would satisfy a long felt need within the industry and would enable machine tool equipment manufacturers and users to save substantial expenditures of time and money.